When you get so mad that you throw something, but you are tired of saying yeet so instead you say yeet bon fleet. Yeet Bon Fleet originated from a random kid that one day said it, and decided to stick with it. Yeet Bon Fleet can also be described as this:
"Yeet Bon Fleet. Bon is French for good. Yelling Yeet Bon Fleet in a public restroom or McDonalds gives good luck. However, yelling ಈಟ್ ಬಾನ್ ಫ್ಲೀಟ್ ಕೆಟ್ಟದು, or Īṭ bān phlīṭ keṭṭadu, is very bad luck, for it means yeet bon fleet bad.

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.